package mailinglist;

import java.nio.ByteBuffer;

import com.sun.grizzly.ProtocolParser;
import com.sun.grizzly.util.WorkerThread;

/**
 * @author kloh
 *
 */
public class MyProtocolParser implements ProtocolParser<String>{
	
	private ByteBuffer mSavedBuffer;
	private int mSavedPosition;

	private boolean mWantsMoreData;
	private boolean mHasUnparsedData;
	
	private String mMessage;
	
	private static int sDEFAULT_BYTEBUFFER_SIZE = 8192;
	
	/* (non-Javadoc)
	 * @see com.sun.grizzly.ProtocolParser#getNextMessage()
	 */
	public String getNextMessage() {
	
		if (this.mMessage == null)
			this.mMessage = extractMessage();
		
		final String lTmp = new String(this.mMessage);

		this.mMessage = null;
		
		return lTmp;
		
	}

	/* (non-Javadoc)
	 * @see com.sun.grizzly.ProtocolParser#hasMoreBytesToParse()
	 */
	public boolean hasMoreBytesToParse() {
		if (this.mHasUnparsedData)
			System.out.println("I have more bytes to parse!");
		return this.mHasUnparsedData;
	}

	/* (non-Javadoc)
	 * @see com.sun.grizzly.ProtocolParser#hasNextMessage()
	 */
	public boolean hasNextMessage() {
		
		if (this.mMessage == null)
			this.mMessage = extractMessage();
		
		return this.mMessage != null;
		
	}

	/* (non-Javadoc)
	 * @see com.sun.grizzly.ProtocolParser#isExpectingMoreData()
	 */
	public boolean isExpectingMoreData() {
		if (this.mWantsMoreData)
			System.out.println("I want more data to come!");
		return this.mWantsMoreData;
	}

	/* (non-Javadoc)
	 * @see com.sun.grizzly.ProtocolParser#releaseBuffer()
	 */
	public boolean releaseBuffer() {
		
		if (this.mWantsMoreData) {
			reallocateBuffer();
		} else {
			this.mSavedBuffer = ByteBuffer.allocate(sDEFAULT_BYTEBUFFER_SIZE);
		}

		return this.mWantsMoreData;
		
	}

	/* (non-Javadoc)
	 * @see com.sun.grizzly.ProtocolParser#startBuffer(java.nio.ByteBuffer)
	 */
	public void startBuffer(final ByteBuffer pByteBuffer) {
		this.mSavedBuffer = pByteBuffer;
		this.mSavedBuffer.flip();
	}

	private String extractMessage() {
		
		if (!this.mSavedBuffer.hasRemaining()) {
			this.mWantsMoreData = false;
			this.mHasUnparsedData = false;
			this.mSavedBuffer.clear();
			return null;
		}
		
		if (this.mSavedBuffer.remaining() < 36) {
			
			this.mWantsMoreData = true;
			this.mHasUnparsedData = false;
			
			System.out.println("Received incomplete receive file message");
			
			return null;
			
		}
		
		this.mSavedPosition = this.mSavedBuffer.position();

		final byte[] lUUIDAsBytes = new byte[36];
		this.mSavedBuffer.get(lUUIDAsBytes);
		final String lUUID = new String(lUUIDAsBytes);

		System.out.println("Received message for id " + lUUID);
		
		if (this.mSavedBuffer.remaining() < 36 + 36) {
			
			this.mWantsMoreData = true;
			this.mHasUnparsedData = false;
			
			System.out.println("Received incomplete receive file message");
			
			return null;
			
		}
		
		final byte[] lANOTHER_ID_AS_BYTES = new byte[36];
		this.mSavedBuffer.get(lANOTHER_ID_AS_BYTES);
		final String lANOTHER_ID = new String(lANOTHER_ID_AS_BYTES);

		final byte[] lTHIRD_ID_AS_BYTES = new byte[36];
		this.mSavedBuffer.get(lTHIRD_ID_AS_BYTES);
		final String lTHIRD_ID = new String(lTHIRD_ID_AS_BYTES);
			
		final String lMessage = new String(lUUID + lANOTHER_ID + lTHIRD_ID);

		System.out.println("Received receive message: " + lMessage);
		
		if (this.mSavedBuffer.remaining() == 0) {
			this.mHasUnparsedData = false;
			this.mWantsMoreData = false;
		} else {
			this.mHasUnparsedData = true;
			this.mWantsMoreData = false;
			this.mSavedPosition = this.mSavedBuffer.position();
		}
		
		return lMessage;
		
	}

	private void reallocateBuffer() {

		if (this.mSavedBuffer.position() != this.mSavedPosition)
			this.mSavedBuffer.position(this.mSavedPosition);
		
		int lNewBufferSize = this.mSavedBuffer.remaining() == 0 ? sDEFAULT_BYTEBUFFER_SIZE * 2
				: sDEFAULT_BYTEBUFFER_SIZE;
		
		while (lNewBufferSize <= this.mSavedBuffer.remaining())
			lNewBufferSize += sDEFAULT_BYTEBUFFER_SIZE;

		System.out.println("Reallocate WorkerThreads ByteBuffer to " + lNewBufferSize + " b.");
		
		final ByteBuffer lTmpBuffer = ByteBuffer.allocate(lNewBufferSize);
		lTmpBuffer.put(this.mSavedBuffer);

		this.mSavedBuffer = lTmpBuffer;

		((WorkerThread) Thread.currentThread()).setByteBuffer(this.mSavedBuffer);

	}
	
}